Hydraulic grease gun



Aug. 7, 1951 H. E. BALLARD HYDRAULIC GREASE GUN Filed March 28, 1949 INVEN TOR. HERMAN L. 6mm

i 'atented Aug. 7, 1951 Herman E. Ballard, Berkeley, Calif.

Application March 28, 1949, Serial N0. 83,805

1 Claim.

floating piston serving to divide the cylinder into an outer lubricant containing chamber and into an inner working medium containing chamber.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where that form of the invention which has been selected for illustration in the drawings accompanying and forming a part of the present specification is outlined in full. In said drawings, one form of the invention is shown, but it is to be understood that it is not limited to such form, since the invention as set forth in the claim may be embodied in a plurality of forms.

Referring to the drawings:

Fig. 1 is a longitudinal mid-section taken through a grease gun embodying the objects of my invention;

Fig. 2 is a partial section taken on the section line 22 of Fig. l.

As shown in these figures, the objects of my invention have been embodied in a grease gun including a cylindrical base I within which is incorporated a piston pump generally designated by the reference numeral 2. Threaded intp a bore 3 formed in the base member I is a cylinder 4 provided with an inner inlet opening 5 communicating with a passageway 6 formed in the base I and with an outer outlet I communicating with a passageway 8 formed in the base I. Disposed intermediate the ends of the passageway 8 is a ball check 9 backed by a light spring I0 receivable in a bore II formed in the base I coaxially with its bore 3. Threaded in the outer end of the bore II in contact with the outer end of the spring I0 is a plug l2. Also formed in the base I are a pair of parallel laterally offset passageways I3 and I4 intersected by a threaded transverse passageway I5, terminating at its inner end in a conical seat I6. Receivable in the seat I6 is the tapered end II of a screw [3, the screw I8 being threaded into the passageway I5 and serving as a means for establishing communication between the offset passageways I3 and I4.

Operatively disposed Within the cylinder 4 is a piston I9. The lower end of the cylinder 4 is sealed to the base member I by a copper gasket 2| and the piston I9 is sealed to the upper end of the cylinder 4 by a rubber O-ring 22. Provided on the upper outer end of the piston I9 are a pair of transversely spaced upwardly extending ears 23 and receivable between and pivoted to these ears by a pin 24, is a lug 25 depending from and formed integral with a clamp 26. Welded to and within the clamp 23 is a sleeve Z'i terminating at its right hand end in a flat 2B. Formed integral with and extending upwardly from the base member I are a pair of parallel, transversely spaced lugs 29 and pivoted to these lugs by a pin 3I is a link 32 having a bifurcated upper end 33 pivoted to the flat 23 by a pin or bolt 34. Telescopically receivable in the sleeve 2'! is a handle 35 terminating in a wrench 33.

Disposed over the right-hand face of the base member I is a collapsible elastomer bag 31 formed with an outwardly extending flange 33. Surrounding the bag 33 immediately to the rear of its flange 38 is a washer 39 and circumscribing the bag 31 is a cylindrical shield 4| threaded to the base member I and provided with an inwardly extending flange 42 arranged to seat against the outer face of the washer 33 and to seal the bag flange 38 against the right-hand face of the base member I. Threaded over the outer end of the shield 41 is a cap 43 provided with a central opening 44 for the ingress of air.

Threaded to the left-hand face of the base member I in sealing engagement with a leather washer 45 is a lubricant cylinder 46. Operatively disposed within the cylinder 46 and dividing it into an expansible working medium containing chamber 47 and an expansible grease containing chamber 48 is a floating piston 49 provided at either end with leather cup seals 5| and 52. Threaded to the outer end of the cylinder 46 is a cap 53 formed with a tapered threaded outlet 54 by which the chamber 48 can be placed in communication with any piece of mechanism such as a valve which is to be lubricated.

To place a grease gun of the character above described in operation, the collapsible bag 31 is filled with any desired liquid working medium such as a light oil, this preferably being done with the bag under the influence of a partial vacuum. This having been done and with the piston I9 in its lowermost position as shown in Fig. 1, so that it serves to close the intake 6, a stick of semi-solid grease is introduced into the 3 chamber 48 by removingthe cap 53. The cap 53 is then replaced and'the outlet 54 connected with the valve to be lubricated. A rotation of the outer end of the handle 35 in a clockwise direction about the pin 34 serves to elevate the piston l9 and in so doing creates a partial vacuum within the lower end of the cylinder 4, the check valve 9 being closed during the upward stroke of the piston. When the lower end of the piston l9 has moved to a point above the intake 5, working medium contained within the resilient elastomer bag 31 will pass through the passageway 6 and through the intake 5, into the lower end of the cylinder 4. This result is brought about due to the fact that the exterior of the bag 37 is always subjected to atmospheric pressure, whereas the working medium within the bag is under the partial vacuum created within the lower end of the cylinder 4 by the upward travel of the piston l9. Upon the downward stroke of the piston is brought about by rotating the handle 35' in a counter-clockwise direction, the piston 19 will close the intake 5 and consequently the working medium trapped beneath the piston 9 within the lower end of the. cylinder will be forced downwardly through the outlet 1, depressing the ball check 9 and passing through the outlet or passageway 8 into the working medium chamber 41 of the cylinder 46. A repetition of the cycle of operation will of course result in the filling of the working medium chamber 4? with the working medium and in thereafter forcing the floatprovided a positively acting grease gun of simple construction wherein grease is dispensed under the action of a floating piston, wherein the floating piston is hydraulically operated by a manually operated piston pump, and wherein working medium is delivered to the manually operated pump under a diiTerential pressure brought about by the external pressure to which the bag 31 is subjected and the partial vacuum to which the working mediumis subjected upon the upward or outward stroke of the piston I9.

I claim:

An hydraulic grease gun comprising: a base member; a lubricant cylinder fixed directly to one side of said base member; an elastomer bag sealed to the opposite side of said base member;

' an open ended working medium pump cylinder ing piston '49 to the left as viewed in Fig. 1 in predetermined increments depending upon the effective volume of the cylinder 4.

When the piston 39 has reached the end of its operative stroke and it is desired to recondition the gun for further use, the screw I8 is unscrewed to an extent suflicient to establish communication between the passageways l3 and I4, the cap 53 of the lubricant cylinder 45 is removed (con veniently by the aid of the Wrench 36), a new stick of grease is inserted in the lubricant chamber 28 and forced inwardly so that the movement of the plunger 49 to the rightas viewed in Fig. 1 will result in forcing the working medium contained in the chamber 4! through the intercommunicating passageways l3 and M back into the bag 31. The cap 53 is then replaced, whereupon the gun is ready for further use. 7

In recapitulation, it will be seen that I have provided in said base member with its axis transverse to the axis of said lubricant cylinder, said pump cylinder and base member being provided with a passageway for establishing communication between said elastomer bag and the interior of said pump cylinder at a point intermediate its ends and said base member being provided'with a passageway. for establishing communication between the inner ends of said pump and lubricant cylinders; a spring biased check valve mounted in said latter passageway for permitting working medium from said pump cylinder to enter said lubricant cylinder; a working medium piston mounted in said pump cylinder and arranged to open and close the said passageway communicating with said elastomer bag; a floating piston mounted in said lubricant cylinder; and a lever mounted on said base member and linked to said working medium piston.

HERMAN E. BALLARID.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,106,144 Harrison Aug. 4, 1914 1,725,720 Pederson Aug. 20, 1929 1,780,888 Webelhoer Nov. 4, 1930 1,867,515 Lassiter July 12, 1932 1,868,060 Grebenstein July 19, 1932 2,097,612 Arnold Nov. 2, 1937 2,352,390 Kirkland June 27, 1944 

